S5L9250B
DATA SHEET
Disc Detect Command (DDTcmd)
Laser diode is automatically turned on.
To detect if a disc is present, the focus actuator searches at the designated speed using the data RAM's
FSSPD(0x20) and FSDELTA(0x21). After this command, the Fepk (S-curve/2) data and SBpk (SBAD/2)'s
information are stored in the buffer so that SYSCON can read it.
Code
1'st byte
01
D7
D6
D5
D4
D3
D2
D1
D0
RPT
DTM1, 0
0
FPKU
0
0
0
RPT: Repeat focus search motion (only possible when DTM1, 0 = 0, 0).
0: Carry out focus search motion only once.
1: Continue focus search motion until RPT = 0, or when STOPcmd's abort bit = 1 is accepted
(maintain sense = "L").
DTM1 -DTM0:
0: Carry out focus search once (auto).
01: Move the focus actuator to Vref position.
10: Raise focus actuator.
11: Lower focus actuator.
FPKU: S-curve detect location (set to 0 in manual mode).
0: Detect when down.
1: Detect when up.
• Search speed can be adjusted using the RAM's FSSPD(0x20), FSDELTA(0x21), FCNTmax(0x28), and
FCNTmin(0x29).
Search speed (1 period) = (FCNTmax-FCNTmin)*2*FSSPD/FSDELTA/Fs
• FE peak can be read through the MICOM interface after one search.
• The following are the data that MICOM can refer to after DDTcmd:
- FEpk: FE peak data (S-curve/2).
- SBpk: SBAD peak data (SBAD/2).
D15
D8 D7
D0
Fepk
SBpk
20